New alloy enables 3D printing of safe steel products

The printing of high-performance steel components for automotive and aerospace applications has come a big step closer. For the first time, a researcher from the University of Kassel has succeeded in using "additive manufacturing", i. e. a special 3D printer to process a steel alloy with exceptionally high damage tolerance, thus making future printed products safer and more reliable.

Although steel alloys have already been used for additive production, a new basic material in combination with the electron beam printing process now delivers a much higher quality in many respects and makes the use of these materials meaningful in many areas of application for the first time, according to professor Thomas Niendorf, a materials scientist from the University of Kassel.

To develop their material, the researchers followed an unprecedented path: they use a so-called TRIP steel alloy as the basis, which demonstrates excellent stability due to its special deformation mechanisms. The heat available in the electron beam pressure process is used in such a way that the unpredictability of the material properties, which has often been problematic up to now, is avoided. The result is a better internal material structure in the end product; this protects against unexpected breakages and other possible damage.

According to Niendorf, applications in the aerospace and automotive industries, currently the drivers behind the technological development of 3D printing, will benefit considerably the result of Niendorf’s research. The additive process is particularly suitable for complex, small components. So far, titanium alloys have dominated 3D printing with metals. In contrast to the titanium products, the steel components printed with the new process do not have to be reworked at great expense, which makes them much cheaper to produce.

In metal 3D printing, products are built up in micrometer-thin layers. For this purpose, metal powder is melted by an electron beam, laser or other heat sources. Due to this method, very filigree, complex and at the same time resilient structures are possible.

Niendorf's research group developed the alloy and the process together with colleagues from the TU Bergakademie Freiberg. The results were published in the latest issue of the renowned scientific journal Scientific Reports, an Open Access Journal of the Nature publishing group.